Water Balance and Patterns of Mineralization of Closed Lake Chany

Abstract

We calculated the water balance and investigated the mineralization of water in closed Lake Chany. the largest lake in Western Siberia in terms of its water area and of great ecological and fisheries importance. The most important natural characteristic of the lake is the cyclic fluctuation of the water level caused by the variability in the overall humidity of the Ob-Irtysh interfluve. The water level regime of Lake Chany is the main natural factor influencing its water-ecological state. Changes in water level are determined by the ratio between the inflow and discharge in its water balance. The modern water balance of Lake Chany (after the separation of the Yudinskii reach) was calculated for hydrological years, and the previously calculated values of its components were refined using a new digital elevation model. It was found that the most significant influence on the water level fluctuation comes from changes in the discharge of the Kargat and Chulym rivers feeding the lake, which is confirmed by a high correlation coefficient between the river inflow and the level increment. Comparison of the curve of changes of the average annual level of Lake Chany and the differential integral curve of the total annual flow of the Kargat and Chulym rivers shows that the main phases of fluctuations in the water level in the lake and the river inflow coincide. The values of mineralization of the lake water changes with fluctuations in water storage. Results of investigations made in 2002 and 2004 were used in carrying out the zoning of the lake water area according to the mineralization of water. The heterogeneity of water salinity is explained by the morphology of its basin without outflow, a low water exchange between different parts of the lake, and by the desalinating effect of the waters of its feeding rivers.